CONTENTS | INDEX | PREV | NEXT


Introduction


GCompare generates patch files for the distribution of updates for any files.

Such a patch file contains only the differences between the old and the new
files. This reduces considerably the size of the data you have to distribute. 


GPatch applies these patches.


The features of GCompare/GPatch are:

 

-The patch file can contain patches for any number of files.
So you can distribute the update for a lot of versions in one file.
If the directory structure of your product is unchanged, then the patcher
will find the required patches without any additional actions of your update
script.
And you can put the patches for different files of your product in one
patch file.


-If the patchfile contains the changes from each version of your program to
the next then it is not necessary to store all old versions.


-The format of the patchfile is very high optimized.
GCompare can try some different coding algorithms and select that with the
shortest result.

I do not know too many similar programs, but I think in the most cases
GCompare produces the shortest patch files of all available patch programs.


-To avoid corrupt files, the programs contain a very safe error checking
(CRC32 signatures for all files). So you can be sure that the result of the
patch process is perfect if no error messages appear.


-GCompare searches matching data in the entire file, not only in a relative
area. I think, it is at the moment the only one doing that.

But because such a search is a laborious process, the program uses a three-dimensional
search array and can do it in a relative short time. If it cannot find enough
memory for the array, it uses a two- or one-dimensional array.